Method and apparatus for optimization in workflow management systems

ABSTRACT

Activities within a workflow are either data management activities (DMAs) or non-DMAs. A workflow is typically carried out by a system by executing one activity after the other. This can, however, be very time consuming. A method and system are provided for optimizing a group of activities (GOA) comprising a DMA, whereby the GOA is comprised in the workflow to improve the overall performance. The method determines the DMAs, and for each DMA, a data level statement (DLS). The GOA is determined and a process graph model (PGM) is determined from the GOA so that the DLS is comprised in the PGM and the semantics of the PGM are identical to those of the GOA. The PGM is optimized for which an optimized GOA is determined. The semantics of the optimized GOA are identical to those of the GOA. In the workflow, the GOA is replaced by the optimized GOA.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the optimization of activitiescomprised in a workflow, in general, and to the optimization of datamanagement activities comprised in a workflow, in particular.

2. Discussion of Related Art

Workflow management systems (WFMSs) are employed for the modelling andexecution of business processes. Business processes specify which pieceof work of a network of pieces of work is carried out in which sequence,and which resources are exploited to carry out the pieces of work.Individual pieces of work may be distributed across a multitude ofdifferent computer systems connected by some type of network. In aworkflow management system, such as the product MQSeries workflow fromIBM Cooperation, business processes are modelled as a network ofactivities. This network of activities is constructed using a directed,acyclic, weighted, colored graph as a meta model. The nodes of the graphrepresent the activities, which define individual tasks to be carriedout. Any other meta model, such as a hierarchical meta model, may beused for constructing process models. In general, each of the activitiesis associated with a piece of code that implements the appropriate taskfor that activity. The edges of the graph, or the control links,describe a potential sequence of execution of the activities. Controllinks are also referred to in the following as links and are representedas arrows; the head of an arrow describes the direction in which theflow of control is moving through the process.

The activity where the control link starts is called the source activityand the activity where the control link ends is called the targetactivity. An activity may be a source and a target activity fordifferent control links. Activities that have no incoming control linkare called start activities, as they start the process. Activities thathave no outgoing control link are called end activities, since aftertheir completion the process has ended. An activity may be a startactivity as well as an end activity. An activity that has multipleoutgoing control links is called a fork activity and an activity withmultiple incoming control links is called a join activity.

Different languages are available in order to implement a workflow intoa workflow management system, and business process execution language(BPEL) is one such language. BPEL may be described as an XML basedlanguage that allows task sharing for a distributed computingenvironment using a combination of web services.

The term BPEL is sometimes also used to refer to other versions of thelanguage, such as business process execution language for web services(BPEL4WS) or BPELWS. BPEL may also be described as a standard fordescribing and choreographing business process activities.

WebSphere Business Integration (WBI) products from IBM Cooperationprovide an implementation for designing and executing BPEL basedbusiness processes. A component of WBI is named WebSphere ProcessChoreographer (WPC) workflow system.

The activities constituting a workflow can be distinguished basicallyinto two different types.

-   -   Data management activities (DMAs): DMAs describe specific nodes        in a workflow and express primarily data management activities,        such as SQL statements, stored procedures, XQuery expressions,        etc.    -   Non-DMAs: Non-DMAs describe specific nodes in a workflow that        are not DMAs. A special type of a non-DMA is a convertible        non-DMA. A convertible non-DMA can be converted into a DMA.

In a WFMS, a workflow is typically executed as a sequence of activities.Thus, each activity is handled one after the other. The execution ofseveral DMAs one after the other can, however, be very time consumingespecially if these DMAs relate to large amounts of data distributedover multiple computer systems of a network.

There is therefore a need for a method and system by which the overallperformance of a workflow that comprises DMAs can be increased.

SUMMARY OF THE INVENTION

The present invention provides a data processing method for optimizing agroup of activities (GOA), whereby the GOA is comprised in a workflow,and whereby the GOA comprises at least one DMA. The data processingmethod in accordance with the present invention comprises the steps ofdetermining the at least one DMA, and determining for each of the atleast one DMA at least one data level statement (DLS). The GOA is thendetermined, from which a process graph model (PGM) is determined,whereby the PGM comprises each of the at least one DLS, and whereby thesemantics of the PGM are identical to the semantics of the GOA. Anoptimized PGM is determined from the PGM. Additionally, an optimized GOAis determined from the optimized PGM, whereby the semantics of theoptimized GOA are identical to the semantics of the optimized PGM. Inthe workflow, the GOA is replaced by the optimized GOA.

The present invention is particularly advantageous as it provides anoptimized GOA which replaces a GOA comprised in a workflow. Theoptimized workflow is generally executed faster than the originalworkflow. The method in accordance with the present invention thereforecontributes to an improvement of the overall performance of a WFMS.

In an embodiment of the present invention, the workflow furthercomprises at least one convertible non-DMA for which at least one DMA isdetermined by the method in accordance with the present invention. Thishas the advantage that activities that have initially been non-DMAactivities are optimized by the method in accordance with the presentinvention. This contributes to an improvement of the overall performanceof the optimized workflow.

In another embodiment of the present invention, at least one DMA isdetermined for which at least one DLS is determined by use of a tagbeing assigned to each of the at least one DMA, whereby each tagcomprises meta information describing the DLS, or by use of a registeredfunction, wherein the registered function is adapted to receive the atleast one DMA and returns the meta-information for the at least one DLS.

It is particularly advantageous to determine DMAs by tags that comprisemeta-information about the DLS, since the method in accordance with thepresent invention only has to scan the workflow description determiningthe DMAs and the corresponding DLSs.

The data processing method in accordance with the present inventionprovides a register for the registration of functions. A user can, forexample, specify functions so that the method in accordance with thepresent invention can be adapted to determine DMAs and the correspondingDLS. This has the advantage that the method in accordance with thepresent invention can be very flexible and can be adapted easily.

If a WFMS does not provide meta information about DMAs in form of tagsor does not know which activities built by other products are DMAs, theuser of the WFMS can register the DMAs and the corresponding functionsfor transforming the DMAs into DLSs.

In another embodiment of the present invention, the GOA comprises asequence of data management activities (DMAs), whereby the sequence ofDMAs relates to an information management system (DBMS), which comprisesan optimization component. The optimized PGM is determined from the PGMby the method in accordance with the present invention by use of theoptimization component. It is particularly advantageous to use theoptimization component, since an already existing, highly developedcomponent can be employed. This saves time and money for the developmentof a method and system in accordance with the present invention.

In another embodiment of the present invention, the PGM comprises apattern and the optimized PGM is determined from the PGM by optimizingthe pattern. The present invention is particularly advantageous as itenables the optimization of frequently occurring patterns that compriseDMA, since it is sometimes hardly possible to optimize such patterns byuse of an optimization component.

In another embodiment of the present invention, the GOA comprises anactivity for performing a loop operation, whereby the activity comprisesa DMA. A DLS is determined for the DMA, and a PGM is determined, wherebythe PGM comprises a pattern which comprises the activity for performingthe loop operation and the DLS. The optimized PGM is determined from thePGM by optimizing the pattern. The present invention is particularlyadvantageous as it enables the optimization of patterns that comprise aloop operation over a DMA. The reason is that such a pattern isfrequently occurring in workflows.

In another embodiment of the present invention, the GOA comprises anactivity for performing a loop operation, whereby the activity forperforming the loop operation comprises a DMA and a web service (WS). ADLS is determined for the DMA and the WS, and a PGM is determined,whereby the PGM comprises a pattern which comprises the activity forperforming the loop operation and the DLS. The optimized PGM isdetermined from the PGM by optimizing the pattern. The present inventionis particularly advantageous as it enables the optimization of patternsthat comprise a loop operation over a DMA and a WS. The reason is thatsuch a pattern is frequently occurring in workflows.

In another embodiment of the present invention, the GOA comprises anactivity for performing a loop operation, whereby the activity forperforming a loop operation comprises a DMA and a transition condition(TC). A DLS is determined for the DMA and the TC. A PGM is determined,whereby the PGM comprises a pattern which comprises the activity forperforming the loop operation and the DLS. The optimized PGM isdetermined from the PGM by optimizing the pattern. The present inventionis particularly advantageous as it enables the optimization of patternsthat comprise a loop operation over a DMA and a TC. The reason is thatsuch a pattern is frequently occurring in workflows.

The method in accordance with the present invention is, however, notlimited to the optimization of the pattern described above. Morecomplicated patterns (e.g., patterns comprising several DMAs, WSs, andTCs) can be optimized.

In another embodiment of the present invention, the workflow comprisesat least one workflow variable that is used in the GOA, but not in theoptimized GOA. This variable is redundant and eliminated in the workflowif it is additionally redundant with respect to the complete workflow.The dropping of a redundant variable leads generally to an improvementof the overall performance of the workflow.

In a further embodiment of the present invention, the at least one DLSis determined for each of the at least one DMA by use of an interactiveor collaborative optimization component. An interactive or collaborativeoptimization component is a component which requests a user to assistduring the optimization (e.g., to determine a DLS for a DMA). This hasthe advantage that the scope and quality of the optimization can beimproved, especially in the case when meta-information about thebehavior of the activity is missing or cannot be determinedprogrammatically.

In another aspect, the present invention relates to a computer programproduct which comprises computer executable instructions in order toperform the method.

In another aspect, the present invention relates to a data processingsystem for optimizing a GOA which is comprised in a workflow, wherebythe GOA comprises at least one DMA and whereby the data processingsystem comprises means for determining the at least one DMA, means fordetermining for each of the at least one DMA at least one DLS, means fordetermining the GOA, means for determining a PGM, whereby the PGMcomprises each of the at least one DLS, and whereby the semantics of thePGM are identical to the semantics of the GOA. The system in accordancewith the present invention further comprises means for determining anoptimized PGM from the PGM, means for determining an optimized GOA fromthe optimized PGM, whereby the semantics of the optimized GOA areidentical to the semantics of the optimized PGM, and means for replacingin the workflow the GOA by the optimized GOA.

The method and system in accordance with the present invention areparticularly advantageous because one or several group of activities(GOAs) comprised in a workflow are replaced by one or more optimizedGOAs, whereby the semantics of the one or several GOAs are leftunchanged and whereby the overall performance of the workflow istypically improved.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, preferred embodiments of the present invention will bedescribed in greater detail by way of example only and making referenceto the drawings in which:

FIG. 1 depicts a block diagram of a workflow system;

FIG. 2 depicts schematically how an optimized GOA is determined;

FIG. 3 illustrates how a first pattern is optimized;

FIG. 4 illustrates how a second pattern is optimized;

FIG. 5 illustrates how a third pattern is optimized;

FIG. 6 illustrates how a fourth pattern is optimized;

FIG. 7 depicts an example of a workflow;

FIG. 8 depicts the annotation phase of a workflow;

FIG. 9 depicts those GOAs comprised in the workflow that consist only ofDMAs;

FIG. 10 depicts the GOAs comprised in the workflow and that take theapplicability of pattern II into account;

FIG. 11 depicts the merger of two optimized GOAs;

FIG. 12 shows an optimized workflow replacing the original workflow.

DETAILED DESCRIPTION

FIG. 1 depicts a block diagram 100 of a workflow system 102. Theworkflow system 102 comprises a microprocessor 104, a volatile memorydevice 106, a non-volatile memory device 108, a workflow design timesystem 110, an information management system 112, and a graphical userinterface 132.

The workflow design time system 110 comprises a data processing system114 in accordance with the present invention and a workflow descriptioneditor 118. The workflow design time system 110 enables a user to createa graphical representation of a workflow 128 on the graphical userinterface 132. The workflow description editor 118 generates, byemployment of the microprocessor 104, a workflow description 136 (forexample in BPEL) from the graphical representation of the workflow 128.The workflow description 136 is stored on the non-volatile memory device108. Alternatively, the workflow description is stored on the volatilememory device 106.

In operation, the data processing system 114 determines a DMA 134 whichis comprised in the workflow description 136 and determines further forthe DMA a data level statement (DLS) 119. The data processing system 114identifies a group of activities (GOA) 124 which comprises the DMA 134.A process graph model 120 is then determined so that the semantics ofthe PGM 120 are identical to the semantics of the GOA 124, whereby thePGM 120 comprises the DLS 119.

The GOA 124 can, for example, comprise a sequence of data managementactivities (DMAs). The corresponding PGM 120 comprises a sequence ofdata level statements (DLSs). DLSs are typically implemented by use ofthe structured query language (SQL).

The information management system 112 comprises an optimizationcomponent 130. The information management system 112 is, for example, adatabase management system (DBMS) and the optimization component 130 is,for example, a multi-query optimizer of a DBMS. If the PGM 120 comprisesa sequence of DLSs, then the optimization component 130 is preferablyused for the determination of an optimized PGM 122.

The method in accordance with the present invention is, however, notrestricted to the optimization of DMAs for which the corresponding DLSsare described by SQL statements. A DLS can also be optimized by themethod in accordance with the present invention if it is described in analternative language, such as, for example, XQuery.

The GOA 124 to be optimized can further comprise activities that arenon-DMAs. For example, the GOA can comprise a convertible non-DMA 138.The manner in which a GOA 124 that additionally comprises a non-DMA isoptimized is described further below by way of example.

The data processing system 114 determines by use of the microprocessor104 an optimized GOA 126 from the optimized PGM 122, whereby thesemantics of the optimized GOA 126 are identical to the semantics of theoptimized PGM 122. The GOA 124 is replaced in the workflow description136 and correspondingly in the graphical description of the workflow 128by the optimized GOA 126 in the workflow description 136. Since thesemantics of the optimized PGM 122 has not changed with respect to thePGM 120, the semantics of the optimized GOA 126 has not changed withrespect to the semantics of the GOA 124.

The data processing system further comprises a register 140. Thatregister comprises a user interface by which a user can specifyfunctions. For example, if a data processing system does not determine aDMA in a workflow, the user can adapt the system by defining a specificfunction that the DMA is determined in the future. Moreover, the usercan be requested, via the user interface, to determine a DLS for a DMSor to provide a specific function by which the system in accordance withthe present invention is able to determine a DLS for a DMS.

As shown in diagram 100, the data processing system 114 can be comprisedin the design time system 110. It can alternatively be integrated intothe run time component of a WFMS. It can also be employed during thedeployment of the workflow.

A workflow may comprise a DMA which relates to a data source and thatthe data source is not yet specified during design time. Hence, the DMAwill not yet be identified as a DMA. Such a DMA would, however, beidentified if the data processing system 114 would be integrated in therun time system. It is therefore particularly advantageous to integratea data processing system in accordance with the present invention intothe run time system of a WFMS.

FIG. 2 depicts schematically a diagram 200 of how an optimized GOA isdetermined by the method in accordance with the present invention. Theworkflow to be optimized as well as the components employed for theoptimization can be assigned to several layers. The first layer isreferred to as process-description-language layer 202. On this layer,the workflow description editor generates a workflow 203 which comprisesan input activity 204, a second activity 206, a third activity 208, afourth activity 210, a fifth activity 212, and an output activity 214.The workflow 203 can, for example, be implemented by use of the businessprocess execution language (BPEL).

The data processing method in accordance with the present inventiondetermines the one or more DMAs comprised in the workflow 203 and thecorresponding DLS. This is indicated in diagram 200 by DMA/DLSdetermination component 216. Additionally, the GOA is determined by useof the DMA as is indicated in diagram 200 by the GOA determinationcomponent 218. The DMA/DLS determination component 216 and GOAdetermination component 218 map from the process-description-languagelayer 202 to the layer which is referred to as process-language andinfrastructure independent layer 228.

On the process-language and infrastructure independent layer 228, thePGM is determined as indicated by the PGM determination component 220.From the PGM, an optimized PGM is determined which is then transformedinto an optimized GOA. This is indicated in diagram 200 by the fieldoptimized PGM/optimized GOA 222. The optimized PGM can, for example, bedetermined by use of a multi-query optimizer 224, whereby themulti-query optimizer is comprised in the infrastructure-dependent layer230. The multi-query optimizer is generally employed for theoptimization if the PGM has a simple structure, for example, if itcomprises a sequence of SQL statements.

Alternatively, the optimized PGM can be determined by the recognition ofpatterns comprised in the PGM. This is described by way of examplebelow. The optimized GOA is determined, for example, by wrapping theoptimized PGM, which can for example be given by a sequence of SQLstatements, into one or more activities. Additionally, SQL artifacts 226can be generated during the determination of the optimized PGM. Theoptimized GOA replaces in the workflow 203 the GOA which has beendetermined by GOA determination 218.

As mentioned above, the optimization component of the informationmanagement system can be used to determine an optimized PGM if the PGMcontains DLSs, such as only a sequence of SQL statements. Alternatively,the optimized PGM can be determined by the recognition of patterns thatare comprised in the PGM.

Generally, four classes of scenarios referred to as optimizationpatterns are frequently occurring in workflow management systems. Themethod in accordance with the present invention is particularly suitedfor optimizing these four patterns within a workflow management system.Detailed information on each pattern is provided in the following, byway of example only, and concrete instantiations are listed as well.

FIG. 3 illustrates how pattern I is optimized. Pattern I ischaracterized in that it comprises a sequence of DMAs. However, themethod in accordance with the present invention is not restricted to theoptimization of sequences. It is also possible to optimize a flow ofDMAs. Diagram 300 is only an example of a pattern in which the GOA to beoptimized only comprises DMAs.

FIG. 3 can be divided into the parts 302 and 304, whereby part 302represents the DMA level of the workflow (corresponding to theprocess-description language layer) and part 304 represents the DLSlevel of the workflow (corresponding to the infrastructure dependentlayer). The initial group of DMAs to be optimized in accordance with thepresent invention comprises a sequence of DMAs, DMA₁ 306 and DMA₂ 308.The arrow pointing from DMA₁ 306 to DMA₂ 308 indicates that DMA₁ 306 isexecuted before DMA₂ 308.

In the example given in diagram 300, DMA₁ 306 and DMA₂ 308 are two SQLstatements wrapped into the activities. On the DLS level 304, thesequence of DMA₁ 306 and DMA₂ 308 corresponds to the sequence of SQLstatements 312 and 314, whereby SQL statement 312 is:

SELECT * FROM :T; and SQL statement 314 is:

SELECT A;B FROM :T;

The SQL statements 312 and 314 are obtained from unwrapping the SQLstatements comprised in DMA₁ and DMA₂, respectively. The sequence of SQLstatements 312 and 314 is preferably optimized by an optimizationcomponent of an information management system, which can, for example,be a multi-query optimizer. The result of the optimization is SQLstatement 316, which reads as:SELECT A; B FROM (SELECT * FROM:T);The sequence of SQL statement 312 and 314 is thus transformed into oneSQL statement 316, whereby the semantics of the SQL sequence 312, 314and the SQL statement 316 are identical.

The SQL statement 316 is then transformed back to the DMA level 302which yields DMA_(1,2) 310. The transformation is, for example, carriedout by wrapping the SQL statement in DMA_(1,2). The semantics ofDMA_(1,2) 310 and the sequence of DMA₁ 306 and DMA₂ 308 are alsoidentical. The advantage of executing DMA_(1,2) instead of DMA₁ and DMA₂is however that DMA_(1,2) is generally processed faster.

FIG. 4 illustrates how pattern II is optimized. Pattern II ischaracterized in that it comprises a tuple to set optimization processin accordance with the present invention. Diagram 400 of FIG. 4 can bedivided into the parts 402 and 404, whereby part 402 represents the DMAlevel of the workflow (corresponding to the process-description languagelayer) and part 404 represents the DLS level of the workflow(corresponding to the infrastructure dependent layer).

The initial GOA to be optimized in accordance with the present inventioncomprises a materialization operation 406 and a loop operation over aDMA 408. The materialization operation 406 is, in this example, thecommand to read the content of a table T into the set S. The loopoperation over a DMA 408 is a WHILE operation 418 over a DMA 420 whichis only executed if the argument in the WHILE operation 418 is true.

The materialization operation 406 and the loop operation over a DMA 408are identified as a GOA to be optimized because they fulfil pattern II.On the DLS level 404, the materialization operation 406 corresponds tothe SQL statement 412 which reads as:

SELECT V1, V2 from :T;

The semantics of the loop operation over a DMA 408 can be described asshown in the DLS 414 by the following artificial language, which issimilar to SQL:

<for Each V=(V1,V2) in S>

UPDATET2

SET T2.a=: V1

WHERE T2.b=: V2;

The PGM comprising SQL statement 412 and DLS 414 is then optimized bythe method in accordance with the present invention. The result is DLS416 which contains the following SQL statements:

MERGE INTO T2

USING (SELECT V1, V2 FROM T)

AS S

ON T2.b=S.V2

WHEN MATCHED THEN

UPDATE

SET T2.a=S.V1

ELSE IGNORE;

The difference between the PGM and the optimized PGM comprising DLS 416is that the PGM is processed in a tuple-based manner while the optimizedPGM is processed in a set-based manner. The DLS 416 is then wrapped intoa BPEL process which yields DMA_(W) 410, the optimized GOA.

The tuple-based manner of processing data is transformed into aset-based manner of processing data. This is particularly advantageoussince set-based processing of data is typically significantly fasterthan tuple-based data processing.

FIG. 5 illustrates how pattern III is optimized. Pattern III ischaracterized in that it comprises one web service (WS) and one DMA.Data is processed in a tuple-based manner whereas after theoptimization, data is processed in a set-based manner. Diagram 500 ofFIG. 5 can be divided into parts 502 and 504, whereby part 502represents the DMA level of the workflow (corresponding to theprocess-description language layer) and part 504 represents the DLSlevel of the workflow (corresponding to the infrastructure dependentlayer).

The GOA to be optimized in accordance with the present inventioncomprises a materialization operation 506 and a loop operation over aDMA and a WS 508. The materialization operation 506 is, in this example,the command to read the content of table T into the set S. Thecorresponding SQL statement is wrapped into the materializationcomponent 506.

The loop operation over a DMA and a WS 508 contains an SQL WHILEoperation 518, a web service 520 and a DMA 522 that are executed whilethe argument of the WHILE operation 518 is true. Moreover, the webservice 520 uses, for example, a single value from the set S as inputand delivers another value as output. The DMA 522 uses the output of theweb service 520 as a parameter.

The WHILE loop as well as the WS 520 are convertible non-DMAs. Hence,the loop over a DMS and a WS 508 can be transformed to a DLS 514. Thesemantics of DLS 514 can be described by the following artificiallanguage.

<for Each V=(V1, . . . , Vn) in S>

<call WS input (V1)

OUTPUT (V1)>

INSERT INTO T2

VALUES (: . . . , :01, . . . );

whereby WS refers to the web service 520.

On the DLS level 504, the materialization component 506 corresponds tothe SQL statement 512 which is

SELECT *

FROM T;

The method in accordance with the present invention determines a DLS 516which is characterized in that it processes data in a set-based manner.The semantics of the DLS 516 can be represented by use of the artificiallanguage by:

INSERT INTO T2

SELECT . . . , UDF(v1), . . .

FROM T;

whereby UDF is a user defined function calling the web service 520.

The DLS 516, which is generally determined in form of an SQL statement,is wrapped into the DMA_(w) 510. Thus, the GOA which comprises thematerialization component 506 and the loop over a WS and a DMA 508 hasbeen optimized to an optimized GOA which comprises DMA_(w) 510. Thetuple-based manner of processing data is thus transformed into aset-based manner of processing data. Activities which process data in aset-based way are usually executed faster than activities that areexecuted in a tuple-based way. Hence, the method in accordance with thepresent invention improves the overall performance of a workflow thatcomprises a GOA with at least one DMA and at least one WS.

FIG. 6 illustrates how pattern IV is optimized. Pattern IV ischaracterized in that it comprises at least one DMA and a transitioncondition (TC). Diagram 600 of FIG. 6 can be divided into the parts 602and 604. Part 602 represents the DMA level (corresponding to theprocess-description-language layer) and part 604 represents the DLSlevel of the workflow (corresponding to the infrastructure dependentlayer).

The GOA to be optimized in accordance with the invention comprises thematerialization operation 606 and of the loop operation over two DMAcomprising two transition conditions 608. The materialization operationis a convertible non-DMA which is, in this example, a command to readthe content of a table T into the set S.

The loop operation 608 contains a WHILE operation 616, a DMA₁ 622, aDMA₂ 624 and the transition conditions 618 and 620. DMA₁ 622 is onlyexecuted if the argument of the WHILE operation 616 is true and if thetransition condition 618 holds. DMA₂ 624 is only executed if theargument of the SQL operation 616 is true and if condition 620 holds. Onthe DLS level 602, the materialization operation 606 relates to the DLS626 which is given in form of an artificial language employed torepresent the semantics of DLS 626:

SELECT*

FROM T;

Additionally, the loop operation 608 relates to the DLS 628 which isgiven in form of an artificial language employed to represent thesemantics of DLS 628:

<for Each V=(V1, . . . , Vn) in S>

BRANCH 1

TRANSITION CONDITION TC1:

UPDATE T2 SET T2.a=:V1

WHERE=(V);

BRANCH 2

TRANSITION CONDITION TC2:

UPDATE T2 SET T2.A=2*:V1

WHERE=(V);;

Note that the DLS 628 corresponds to a tuple-based processing of the setS. The PGM comprising DLSs 626 and 628 is optimized by the method inaccordance with the present invention. The result is the optimized PGMwhich is given by DLS 630. DLS 630 corresponds to a set based processingof the set S. DLS 630 is given by the SQL statement:

UPDATE T2 SET T2.A=:V1

WHERE TC1;

UPDATE T2 SET T2.A=2*:V1

WHERE TC2;

The DLS 626 is then transformed into the optimized GOA which correspondsin this example to DMA 610, DMA_(1w) 612 and DMA_(2w) 614. DMA 610restricts the scope of the DMA to the elements v in S. DMA_(1w) is onlyexecuted if TC1 holds and processes a single element of S. DMA₂, is onlyexecuted if TC2 holds and processes only a single element of S.

In the preceding paragraphs, the four patterns preferably optimized bythe method in accordance with the present invention have been described.The pattern optimization depends on the possibility of determining DMAsin the workflow and of determining a GOA. The way the method inaccordance with the present invention determines the DMAs and the GOAsis described in the following by way of an example.

FIG. 7 depicts a diagram 700 of a workflow implemented in BPEL by use ofthe WebSphere Integration developer from IBM Corporation. Thecorresponding BPEL code is schematically given in an abridged form inthe following:

-   1. <?xml version=“1.0” encoding=“UTF-8”?>-   2. <bpws:process    xmlns:bpws=“http://schemas.xmlsoap.org/ws/2004/03/business-process/”    . . . >-   3. . . .-   4. <bpws:variables>-   5. <bpws:variable name=“ResultSet1” type=“ns1:tSetReference”    wpc:id=“10”/>-   6. <bpws:variable name=“ResultSet2” type=“ns1:tSetReference”    wpc:id=“11”/>-   7. <bpws:variable name=“ResultSet3” type=“ns1:tSetReference”    wpc:id=“12”/>-   8. <bpws:variable name=“ResultSet4” type=“ns1:tSetReference”    wpc:id=“13”/>-   9. <bpws:variable name=“SingleOrder” type=“xsd:anyType”    wpc:id=“14”/>-   10. <bpws:variable name=“DataSource” type=“ns1:tDataSource”    wpc:id=“19”/>-   11. <bpws:variable name=“RetrievedResultSet4” type=“xsd:anyType”    wpc:id=“22”/>-   12. </bpws:variables>-   13. <bpws:sequence name=“HiddenSequence” wpc:id=“1073741826”>-   14. <bpws:receive createInstance=“yes” name=“Receive”    operation=“operation1” partnerLink=“Client”    portType=“ns0:SourceProcess” wpc:displayName=“Receive” wpc:id=“3”>-   15. <wpc:output>-   16. <wpc:parameter name=“input1” variable=“Input1”/>-   17. </wpc:output>-   18. </bpws:receive>-   19. <bpws:flow name=“ParallelActivities”    wpc:displayName=“ParallelActivities” wpc:id=“6”>-   20. <bpws:links>-   21. <bpws:link name=“Link1” wpc:id=“16”/>-   22. <bpws:link name=“Link2” wpc:id=“17”/>-   23. <bpws:link name=“Link3” wpc:id=“18”/>-   24. </bpws:links>-   25. <bpws:invoke name=“GermanOrders” operation=“null”    partnerLink=“null” portType=“ns2:null”    wpc:displayName=“GermanOrders” wpc:id=“7”>-   26. <dma:dataManagementActivity    xmlns:dma=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma”    xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”    xsi:schemaLocation=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma    http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma/dataManagementActivity/dma.xsd”    xsi:type=“dma:tSqlDma”>-   27. <dma:statement>-   28. <dma:dataSource variable=“DataSource”/>-   29. <dma:resultSetReference variable=“ResultSet1”/>-   30. <dma:body><![CDATA[SELECT OID, CID,    convertEuro2Dollar(TOTPRICE), ITEMID, QUANTITY, DATE FROM    myschema.germanorders]]></dma:body>-   31. </dma:statement>-   32. </dma:dataManagementActivity>-   33. <bpws:sources>-   34. <bpws:source linkName=“Link1”/>-   35. </bpws:sources>-   36. </bpws:invoke>-   37. <bpws:invoke name=“GBOrders” operation=“null” partnerLink=“null”    portType=“ns2:null” wpc:displayName=“GBOrders” wpc:id=“8”>-   38. <dma:dataManagementActivity    xmlns:dma=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma”    xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”    xsi:schemaLocation=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma    http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma/dataManagementActivity/dma.xsd”    xsi:type=“dma:tSqlDma”>-   39. <dma:statement>-   40. <dma:dataSource variable=“DataSource”/>-   41. <dma:resultSetReference variable=“ResultSet2”/>-   42. <dma:body><![CDATA[SELECT OID, CID, convertGBP2Dollar(TOTPRICE),    ITEMID, QUANTITY, DATE FROM myschema.gborders]]></dma:body>-   43. </dma:statement>-   44. </dma:dataManagementActivity>-   45. <bpws:sources>-   46. <bpws:source linkName=“Link2”/>-   47. </bpws:sources>-   48. </bpws:invoke>-   49. <bpws:invoke name=“USOrders” operation=“null” partnerLink=“null”    portType=“ns2:null” wpc:displayName=“USOrders” wpc:id=“9”>-   50. <dma:dataManagementActivity    xmlns:dma=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma”    xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”    xsi:schemaLocation=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma    http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma/dataManagementActivity/dma.xsd”    xsi:type=“dma:tSqlDma”>-   51. <dma:statement>-   52. <dma:dataSource variable=“DataSource”/>-   53. <dma:resultSetReference variable=“ResultSet3”/>-   54. <dma:body><![CDATA[SELECT OID, CID, TOTPRICE, ITEMID, QUANTITY,    DATE FROM myschema.usorders]]></dma:body>-   55. </dma:statement>-   56. </dma:dataManagementActivity>-   57. <bpws:sources>-   58. <bpws:source linkName=“Link3”/>-   59. </bpws:sources>-   60. </bpws:invoke>-   61. <bpws:invoke name=“Orders” operation=“null” partnerLink=“null”    portType=“ns2:null” wpc:displayName=“Orders” wpc:id=“15”>-   62. <dma:dataManagementActivity    xmlns:dma=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma”    xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”    xsi:schemaLocation=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma    http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma/dataManagementActivity/dma.xsd”    xsi:type=“dma:tSqlDma”>-   63. <dma:statement>-   64. <dma:dataSource variable=“DataSource”/>-   65. <dma:resultSetReference variable=“ResultSet4”/>-   66. <dma:body><![CDATA[(SELECT * FROM]]>-   67. <dma:setReference displayName=“RS1”    variable=“ResultSet1”/><![CDATA[) UNION ALL (SELECT * FROM]]>-   68. <dma:setReference displayName=“RS2”    variable=“ResultSet2”/><![CDATA[) UNION ALL (SELECT * FROM]]>-   69. <dma:setReference displayName=“RS3”    variable=“ResultSet3”/><![CDATA[)]]></dma:body>-   70. </dma:statement>-   71. </dma:dataManagementActivity>-   72. <bpws:targets>-   73. <bpws:target linkName=“Link1”/>-   74. <bpws:target linkName=“Link2”/>-   75. <bpws:target linkName=“Link3”/>-   76. </bpws:targets>-   77. </bpws:invoke>-   78. </bpws:flow>-   79. <bpws:invoke name=“RetrieveOrders” operation=“null”    partnerLink=“null” portType=“ns2:null”    wpc:displayName=“RetrieveOrders” wpc:id=“20”>-   80. <dma:dataManagementActivity    xmlns:dma=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma”    xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”    xsi:schemaLocation=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma    http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma/dataManagementActivity/dma.xsd”    xsi:type=“dma:tRetrieveSetDma”>-   81. <dma:statement>-   82. <dma:from variable=“ResultSet4”/>-   83. <dma:to variable=“RetrievedResultSet4”/>-   84. </dma:statement>-   85. </dma:dataManagementActivity>-   86. </bpws:invoke>-   87. <bpws:while name=“ForEachOrder” wpc:displayName=“ForEachOrder”    wpc:id=“21”>-   88. <wpc:documentation>For each t=(OID, CID, TOTPRICE, ITEMID,    QUANTITY, DATE) element of RetrievedResultSet4</wpc:documentation>-   89. <bpws:condition    expressionLanguage=“http://www.ibm.com/xmlns/prod/websphere/business-process/expression-lang/built-in/6.0.0/”>-   90. <wpc:true/>-   91. </bpws:condition>-   92. <bpws:invoke name=“UpdateInventory” operation=“null”    partnerLink=“null” portType=“ns2:null”    wpc:displayName=“UpdateInventory” wpc:id=“23”>-   93. <dma:dataManagementActivity    xmlns:dma=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma”    xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”    xsi:schemaLocation=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma    http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma/dataManagementActivity/dma.xsd”    xsi:type=“dma:tSqlDma”>-   94. <dma:statement>-   95. <dma:dataSource variable=“DataSource”/>-   96. <dma:body><![CDATA[UPDATE myschema.retailer_storage SET amount =    amount - #T.Quantity# WHERE product_id = #T.ITEMID#-   97.]]></dma:body>-   98. </dma:statement>-   99. </dma:dataManagementActivity>-   100. </bpws:invoke>-   101. </bpws:while>-   102. <bpws:reply name=“Reply” operation=“operation1”    partnerLink=“Client” portType=“ns0:SourceProcess”    wpc:displayName=“Reply” wpc:id=“4”>-   103. <wpc:input>-   104. <wpc:parameter name=“output1” variable=“Input1”/>-   105. </wpc:input>-   106. </bpws:reply>-   107. </bpws:sequence>-   108. </bpws:process>

This example of a workflow assumes that received orders 702 are storedin three tables in a database: GermanOrders, GBOrders and USOrders. Thethree correspondingly named activities 704, 706, and 708, respectivelyare selecting the orders out of these tables by applying a currencytransformation function and storing them in new sets. The activityorders 710 is building a union of these sets and stores the resultingset in the database. The resulting set is materialized in the activityRetrieveOrders 712 and the subsequent WHILE loop activity 714 isoperating on the elements of the set and executing a correspondingUpdateInventory 716 statement for each element of this set. The flowsend with the activity Reply 718.

FIG. 8 shows schematically a diagram 800 of the annotation phase. Thetype of an activity is determined by the method in accordance with thepresent invention by tags or meta data attached to the activity or byuse of specific functions provided by the method and system inaccordance with the present invention. It is, for example, tagged inline 30 of the BPEL source code given above that the GermanOrderactivity is a DMA and the corresponding SQL statement is directlyattached to the activity.

In the annotation phase, relevant information is simply added to theworkflow, but the structure of the workflow is left unchanged. In thisembodiment of the present invention, the activities which are identifiedas DMAs by use of attached tags or meta data are marked by the symbolDMA 820.

The retrieve order activity 812 and the WHILE loop activity 814 areidentified as convertible DMAs by use of the underlying meta data or byuse of tags. These activities are marked with the symbol CONV 822. Aconvertible DMA refers to an activity that can be converted to a DMA,because the originally expressed activity could be mapped to aprocessing step issued in the data management layer (e.g., a userdefined function UDF that might call a web service).

Diagram 900 of FIG. 9 depicts additionally the group of DMAs 920 and 922comprised in the workflow. The method in accordance with the presentinvention determines the DMAs that are linked directly as a group ofDMAs to be optimized by the method in accordance with the presentinvention. Thus, activity GermanOrders 904, GBOrders 906, USOrders 908,and orders 910 are identified as a group of DMAs 920 and UpdateInventoryactivity 916 is identified as a second group of DMAs 922. The receivedactivity 902, the RetrieveOrders activity 912, the WHILE loop activity914, and the reply activity 918 are not assigned to a group of DMAssince these activities do not represent any DMA activities. TheRetrieveOrders activity 912 is a materialization operation. Pattern IIcan thus be employed to determine an optimized GOA for the GOAcomprising the RetrieveOrders activity 912, the WHILE activity 914 andthe DMA 916.

This is depicted in diagram 1000 of FIG. 10. The GOA 1022 contains theRetrieveOrder activity 1012, the WHILE loop activity 1014 and theUpdateInventory activity 1016. As mentioned above, the GOA 1022comprising the DMAs 1012, 1014, and 1016 shows a tuple based processingof the data and can be optimized according to an optimization pattern IIinto a set optimized processing. The receive activity 1002 and the replyactivity 1018 are not assigned to a group of DMAs. The GermanOrderactivity 1004, the GBOrders activity 1006, the USOrder activity 1008 aswell as the order activity 1010 are grouped into the GOA 1020 as hasbeen the case in diagram 900. In an embodiment of the present invention,the GOA 1020 and GOA 1022 are optimized separately. GOA 1020 isoptimized by use of pattern I and GOA 1022 is optimized by use ofpattern II. The optimization is done in a first step by application ofthe corresponding patterns to the PGMs that correspond to GOA 1020 and1022, respectively. This results in two optimized PGM, whereby each PGMcomprises one DLS.

The DLS which corresponds to the optimized PGM of GOA 1020 is given by:(SELECT OID, CID, convertEuro2Dollar(TOTPRICE), ITEMID, QUANTITY, DATEFROM myschema.germanorders) UNION ALL (SELECT OID, CID,convertGBP2Dollar(TOTPRICE), ITEMID, QUANTITY, DATE FROMmyschema.gbporders) UNION ALL (SELECT OID, CID, TOTPRICE, ITEMID,QUANTITY, DATE FROM myschema.usorders)

The DLS which corresponds to the optimized PGM of GOA 1022 is: MERGEINTO myschema.retailer_storage USING RetrievedResultSet4 AS orders ONmyschema.retailer_storage.product_id = orders.itemid WHEN MATCHED THENUPDATE SET myschema.retailer_storage.amount =myschema.retailer_storage.amount - orders.quantity

Since the GOA 1020 and GOA 1022 are arranged in a sequence, the two DLSare semantically arranged in a sequence. The two DLS are thus optimizedby application of pattern I. This results into one optimized PGM that issemantically equal to the sequence of the two optimized PGMs mentionedabove. The optimized PGM can then be transformed into an optimized GOA.

Alternatively, the two DLS mentioned above can be used to determine thecorresponding two DMAs. The two DMAs replace GOA 1020 or GOA 1022,respectively in the workflow. The workflow is again optimized byidentifying a GOA that comprises the two DMAs that are then optimizedaccording to pattern I.

FIG. 11 shows a diagram 1100 of two GOAs that are merged into one GOA bythe method in accordance with the present invention. The one GOA can bedetermined alternatively to the two schemes described above in thefollowing way. Since, as depicted in diagram 1000, the two group of GOAsare linked (the order activity 1110 is connected directly to theRetrieveOrders activities 1112), they are grouped by the method inaccordance with the present invention to a single GOA 1120 to beoptimized by the method in accordance with the present invention. Thus,the GermanOrder activity 1104, the GBOrders activity 1106, the USOrdersactivity 1108, the orders activity 1110, the retrieve order activities1112, the WHILE loop 1114, and the UpdateInventory activity 1116, formone GOA 1120 to be optimized. The receive activity 1102 and the replyactivity 1118 are not assigned to the group of DMAs 1120.

The GOA is translated into a PGM which comprises SQL statements. In anembodiment of the present invention, the SQL statements can be directlywrapped into the activities. The PGM can be optimized by theoptimization component of an information management system. Theoptimization component returns a single statement that is semanticallyequivalent to the logic implemented in the source process. The optimizedPGM, which is typically given by one or more SQL statements, is thentransformed into an optimized GOA, which replaces the GOA in theworkflow.

FIG. 12 shows a diagram 1200 of how the optimized GOA is implemented inthe workflow. The original GOA to be optimized as shown in diagram 1100is replaced by the GOA comprising a single DMA 1204 which comprises theSQL statement determined by the optimization component. The DMA 1204 islinked to the activity Receive 1202 and the activity Reply 1206 as shownin diagram 1200. The corresponding BPEL code is schematically given inan abridged form in the following. The SQL statement is wrapped into theBPEL code as can be seen in the lines 10 to 27.

-   1. <?xml version=“1.0” encoding=“UTF-8”?>-   2. <bpws:process . . . >-   3. . . .-   4. <bpws:variables>-   5. <bpws:variable name=“DataSource” type=“ns2:tDataSource”    wpc:id=“7”/>-   6. </bpws:variables>-   7. <bpws:sequence name=“HiddenSequence” wpc:id=“1073741826”>-   8. <bpws:receive createInstance=“yes” name=“Receive”    operation=“operation1” partnerLink=“Client”    portType=“ns0:TargetProcess” wpc:displayName=“Receive” wpc:id=“3”>-   a. <wpc:output>-   b. <wpc:parameter name=“input1” variable=“Input1”/>-   c. </wpc:output>-   9. </bpws:receive>-   10. <bpws:invoke name=“SQL” operation=“null” partnerLink=“null”    portType=“ns1:null” wpc:displayName=“SQL” wpc:id=“6”>-   a. <dma:dataManagementActivity    xmlns:dma=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma”    xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”    xsi:schemaLocation=“http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma    http://www.ibm.com/xmlns/prod/websphere/business-process/v6.0/dma/dataManagementActivity/dma.xsd”    xsi:type=“dma:tSqlDma”>-   11. <dma:statement>-   12. <dma:dataSource variable=“DataSource”/>-   13. <dma:body><![CDATA[MERGE INTO myschema.retailer_storage-   14. USING-   15. ((SELECT OID, CID, convertEuro2Dollar(TOTPRICE), ITEMID,    QUANTITY, DATE-   16. FROM myschema.germanorders)UNION ALL-   17. (SELECT OID, CID, convertGBP2Dollar(TOTPRICE), ITEMID, QUANTITY,    DATE-   18. FROM myschema.gbporders)UNION ALL-   19. (SELECT OID, CID, TOTPRICE, ITEMID, QUANTITY, DATE-   20. FROM myschema.usorders)-   21.) AS orders-   22. ON myschema.retailer_storage.product_id = orders.itemid-   23. WHEN MATCHED THEN-   24. UPDATE SET myschema.retailer_storage.amount =    myschema.retailer_storage.amount - orders.quantity-   25. ELSE IGNORE]]></dma:body>-   26. </dma:statement>-   27. </dma:dataManagementActivity>-   28. </bpws:invoke>-   29. <bpws:reply name=“Reply” operation=“operation1”    partnerLink=“Client” portType=“ns0:TargetProcess”    wpc:displayName=“Reply” wpc:id=“4”>-   a. <wpc:input>-   b. <wpc:parameter name=“output1” variable=“Input1”/>-   c. </wpc:input>-   30. </bpws:reply>-   31. </bpws:sequence>-   32. </bpws:process>

LIST OF REFERENCE NUMERALS

100 block diagram 102 workflow system 104 microprocessor 106 volatilememory device 108 nonvolatile memory device 110 workflow design timesystem 112 information management system 114 data processing system foroptimizing 116 database 118 workflow description editor 119 data levelstatement (DLS) 120 process graph model (PGM) 122 optimized PGM 124group of activities (GOA) 126 optimized GOA 128 graphical representationof a workflow 130 optimization component 132 graphical user interface134 data management activity (DMA) 136 workflow description 138convertible non-DMA 140 register 200 schematic depiction 202process-description language layer 203 workflow 204 activity 206activity 208 activity 210 activity 212 activity 214 activity 216 DMA/DLSdetermination component 218 GOA determination component 220 PGMdetermination component 222 optimized PGM/optimized GOA determination224 multi-query optimization 226 SQL artifacts 228 process-language andinfrastructure independent layer 230 infrastructure dependent layer 300pattern I 302 DMA level 304 DLS level 306 DMA 308 DMA 310 DMA 312 DLS314 DLS 316 DLS 400 pattern II 402 DMA level 404 DLS level 406materialization operation 408 loop operation over a DMA 410 DMA 412 DLS414 DLS 416 DLS 418 WHILE loop 420 DMA 500 pattern III 502 DMA level 504DLS level 506 materialization operation 508 loop operation 510 DMA 512DLS 514 DLS 516 DLS 518 WHILE loop 520 web service 522 DMA 600 patternIV 602 DMA level 604 DLS level 606 materialization operation 608 loopoperation 610 DMA 612 DMA 614 DMA 616 WHILE loop 618 transitioncondition 620 transition condition 622 DMA 624 DMA 626 DLS 628 DLS 630DLS 700 workflow 702 activity Receive 704 activity GermanOrders 706activity GBOrders 708 activity USOrders 710 activity Orders 712 activityRetrieve Orders 714 WHILE loop activity 716 activity UpdateInventory 718reply activity 800 workflow 802 activity Receive 804 activityGermanOrders 806 activity GBOrders 808 activity USOrders 810 activityOrders 812 activity Retrieve Orders 814 WHILE loop activity 816 activityUpdateInventory 818 reply activity 820 Symbol DMA 822 Symbol CONV 900workflow 902 activity Receive 904 activity GermanOrders 906 activityGBOrders 908 activity USOrders 910 activity Orders 912 activity RetrieveOrders 914 WHILE loop activity 916 activity UpdateInventory 918 replyactivity 920 GOA 922 GOA 1000 workflow 1002 activity Receive 1004activity GermanOrders 1006 activity GBOrders 1008 activity USOrders 1010activity Orders 1012 activity Retrieve Orders 1014 WHILE loop activity1016 activity UpdateInventory 1018 reply activity 1020 GOA 1022 GOA 1100workflow 1102 activity Receive 1104 activity GermanOrders 1106 activityGBOrders 1108 activity USOrders 1110 activity Orders 1112 activityRetrieve Orders 1114 WHILE loop activity 1116 activity UpdateInventory1118 reply activity 1120 GOA 1200 workflow 1202 activity receive 1204activity comprising SQL statement 1206 activity reply

1. A data processing method for optimizing a group of activities beingcomprised in a workflow to enhance processing of said workflow, whereinsaid group of activities comprises at least one data managementactivity, and said data processing method comprises: (a) determiningsaid at least one data management activity; (b) determining for each ofthe at least one data management activity at least one data levelstatement; (c) determining said group of activities; (d) determining aprocess graph model from said determined group of activities, whereinsaid process graph model comprises each of the at least one data levelstatements, and wherein the semantics of said process graph model areidentical to the semantics of said determined group of activities; (e)determining an optimized process graph model from said determinedprocess graph model to enable processing of said optimized process graphmodel faster than processing of said process graph model; (f)determining from said optimized process graph model a group ofactivities optimized in accordance with said optimized process graphmodel, wherein the semantics of the optimized group of activities areidentical to the semantics of the optimized process graph model; and (g)replacing said group of activities in said workflow with said optimizedgroup of activities to enhance processing of said workflow.
 2. Themethod according to claim 1, wherein said workflow comprises at leastone convertible non-data management activity, and step (a) furthercomprises: (a.1) determining at least one data management activity foreach of the at least one convertible non-data management activity. 3.The method according to claim 1, wherein the at least one datamanagement activity and the at least one data level statement aredetermined by use of one of: a tag being assigned to each of the atleast one data management activity, wherein said tag comprises metainformation describing the data level statement; and a registeredfunction, wherein said function is adapted to receive the at least onedata management activity and returns said meta-information for the atleast one data level statement.
 4. The method according to claim 1,wherein said determined group of activities includes a sequence of datamanagement activities that relates to an information management system,wherein said information management system comprises an optimizationcomponent, and wherein step (e) further comprises: (e.1) determining theoptimized process graph model from said determined process graph modelby use of said optimization component of said information managementsystem.
 5. The method according to claim 1, wherein step (d) furthercomprises: (d.1) determining a process graph model including a pattern;and step (e) further comprises: (e.1) determining the optimized processgraph model from the determined process graph model by optimizing saidpattern.
 6. The method according to claim 1, wherein said determinedgroup of activities comprises an activity for performing a loopoperation, said activity comprising a data management activity, whereinstep (b) further comprises: (b.1) determining a data level statement forsaid data management activity; step (d) further comprises: (d.1)determining a process graph model comprising a pattern that includessaid activity for performing said loop operation and said data levelstatement; and step (e) further comprises: (e.1) determining theoptimized process graph model from the determined process graph model byoptimizing said pattern.
 7. The method according to claim 1, whereinsaid determined group of activities comprises an activity for performinga loop operation, said activity comprising a data management activityand a web service, wherein step (b) further comprises: (b.1) determininga data level statement for said data management activity and said webservice; wherein step (d) further comprises: (d.1) determining a processgraph model comprising a pattern including said activity for performingsaid loop operation and said data level statement; and step (e) furthercomprises: (e.1) determining the optimized process graph model from thedetermined process graph model by optimizing said pattern.
 8. The methodaccording to claim 1, wherein said determined group of activitiescomprises an activity for performing a loop operation, said activitycomprising a data management activity and a transition condition,wherein step (b) further comprises: (b.1) determining a data levelstatement for said data management activity and said transitioncondition; step (d) further comprises: (d.1) determining a process graphmodel comprising a pattern including said activity for performing theloop operation and said data level statement; and step (e) furthercomprises: (e.1) determining the optimized process graph model from thedetermined process graph model by optimizing said pattern.
 9. The methodaccording to claim 1, wherein the workflow is implemented in a workflowprogramming language and a redundant workflow variable comprised in thedetermined group of activities is eliminated if it is redundant withrespect to the workflow.
 10. The method according to claim 1, whereinstep (b) further comprises: (b.1) determining the at least one datalevel statement for each of the at least one data management activity byuse of one of an interactive and a collaborative optimization component.